1. Field of the Invention
The present invention relates to an apparatus for preventing thermal deformation of a machine tool, which comprises heat exchanging portions designed to dispose in prescribed portions of the machine tool in order to prevent thermal deformation of these portions.
2. Prior Art Description
In machine tools, the electrical energy for driving thereof is inevitably consumed in part in the form of heat, so that machine tools suffer from thermal deformation. Since the thermal expansion rate of steel is as large as about 0.01 mm per meter by elevating one degree of Centigrade, thermal deformation occurred in a machine tool causes to deteriorate machining accuracy thereof. Thus, a conventional machine tool is provided with oil jackets placed around the bearing mechanism of a spindle and the like. A coolant such as a cutting oil is circulated through the oil jackets to prevent the machine tool from excessive heating, whereby the machine tool is adjusted of its thermal balance and is suppressed of its thermal deformation.
However, the provision of the oil jackets causes the machine tool complicated in structure. Further, there is a fear that the inner portions of the oil jackets will rust due to the coolant flowing therethrough. Furthermore, the portions of the machine tool which are cooled by the coolant are limited to the places where the oil jackets are provided, so that in the case that the thermal balance is changed owing to the atmosphere in which the machine tool is placed, the portions to be cooled cannot easily be modified in order to effectively suppress the thermal deformation occurred in the machine tool.
Accordingly, an object of the present invention is to provide an apparatus for preventing thermal deformation occurred in a machine tool, which is capable of suppressing the thermal deformation of the machine tool without causing the machine tool to be complicated in structure.
An another object of the present invention is to provide an apparatus for preventing thermal deformation occurred in a machine tool, which has one or more heat exchanging portions which can easily be attached on desired portions of the machine tool.
Still another object of the present invention is to provide an apparatus for preventing thermal deformation occurred in a machine tool, which is capable of heating and/or cooling desired portions of the machine tool.
Yet another object of the present invention is to provide an apparatus for preventing thermal deformation of a machine tool which is capable of performing suitable heating and/or cooling operations of the desired portions of the machine tool in accordance with an amount of heat transfer to the respective portions of the machine tool by a heat transfer fluid.